It is known in the art that photographic display materials are utilized for advertising as well as decorative displays of photographic images. Since these display materials are used in advertising, the image quality of the display material is critical in expressing the quality message of the product or service being advertised. Furthermore, a photographic display image needs to be high impact, as it attempts to draw consumer attention to the display material and the desired message being conveyed. Typical applications for display material include product and service advertising in public places such as airports, buses and sports stadiums, movie posters and fine art photography. The desired attributes of a quality, high impact photographic display material are a slight blue density minimum, durability, sharpness and flatness. Cost is also important as display materials tend to be expensive compared with alternative display material technology mainly lithographic images on paper. For display materials, traditional color paper is undesirable as it suffers from a lack of durability for the handling, photographic processing and display of large format images.
In the formation of color paper it is known that the base paper has applied thereto a layer of polymer, typically polyethylene. This layer serves to provide waterproofing to the paper, as well as providing a smooth surface on which the photosensitive layers are formed. The formation of a suitably smooth surface is difficult requiring great care and expense to ensure proper laydown and cooling of the polyethylene layers. The formation of a suitably smooth surface would also improve image quality as the display material would have more apparent blackness as the reflective properties of the improved base are more specular than the prior materials. As the whites are whiter and the blacks are blacker, there is more range in between and, therefore, contrast is enhanced. It would be desirable if a more reliable and improved surface could be formed at less expense.
Prior art photographic reflective papers comprise a melt extruded polyethylene layer which also serves as a carrier layer for optical brightener and other whitener materials as well as tint materials. It would be desirable if the optical brightener and tints, rather than being dispersed a single melt extruded layer of polyethylene could be concentrated nearer the surface where they would be more effective optically.
Prior art photographic clear display materials have light sensitive silver halide emulsions coated directly onto a gelatin coated clear polyester sheet. Clear photographic display materials are typically used as overhead materials that are projected on a screen, typically a highly reflective and white and display materials that utilize light boxes with a white diffuser screen. Diffuser screens are necessary to diffuse the light source used to backlight clear display materials and to provide the white portion of the image. Without a diffuser, the light source would significantly reduce the quality of the image. Since light sensitive silver halide emulsions that are used for prior art clear display materials tend to be yellow because of the gelatin used as a binder for photographic emulsions, the minimum density areas of a developed image will tend to appear as a yellow white. A yellow white reduces the commercial value of a transmission display material because the imaging viewing public associates image quality with a blue white. It would be desirable if a clear display material could have a more blue white.
Prior art photographic display material use polyester as a base for the support. Typically the polyester support is from 150 to 250 .mu.m thick to provide the required stiffness. A thinner base material would be lower in cost and allow for roll handling efficiency as the rolls would weigh less and be smaller in diameter. It would be desirable to use a base material that had the required stiffness but was thinner to reduce cost and improve roll handling efficiency.
Prior art photographic clear display materials, while providing excellent image quality, tend to be expensive when compared with other quality imaging technologies such as ink jet imaging, thermal dye transfer imaging, and gravure printing. Since photographic clear display materials require an additional imaging processing step compared to alternate quality imaging systems, the cost of clear photographic display materials can be higher than other quality imaging systems. The processing equipment investment required to process photographic transmission display materials also requires consumers to typically interface with a commercial processing lab increasing time to image. It would be desirable if a high quality clear display support could utilize nonphotographic quality imaging technologies.
Prior art clear base materials for digital printing technologies such as ink jet or thermal dye transfer printing utilize a gelatin coated transparent polyester sheet. Prior art digital transparent polyester sheet tends to be yellow because of the gelatin used as a binder for image receiving layers, the minimum density areas of a developed image will tend to appear as a yellow.
Prior art clear digital display materials typically are image receiving layers coated on a transparent primed polyester sheet. The extra priming operation is expensive as it requires an additional operation and expensive priming materials.